JPS59193007A - Core for stationary induction apparatus - Google Patents

Abstract

PURPOSE:To reduce iron loss and the magnetostriction oscillation, and to reduce the exciting current and noise of the core of a stationary induction apparatus by a method wherein the core is so constructed as to make the ratio between width of the superposing part at the junction part of the core leg and the yoke and width of a steel plate to be nearly constant at the whole laminated blocks. CONSTITUTION:Every laminated steel plate of the same width is made to form one block, and the blocks of the plural number having different widths are assembled to form a single-phase two leg core, for example. Width l of the core leg 1 and the yoke 2 of the block at the central part of the core becomes to the maximum width of the core, superposed width at the superposing part 3 is made to DELTAl, and the ratio thereof becomes to DELTAl/l. While, width of the core leg 1 and the yoke 2 of the block close by the surface layer part of the core is made to 0.5l, and width of the superposing part 3 is made to 0.5XDELTAl. Width of the superposing part 3 is so set as to have the same ratio between width of the steel plate of the same block in regard to every block. Accordingly, constant low iron loss and a low magnetostriction oscillation can be realized in the core, and an exciting current and noise can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an iron core for a stationary inductor such as a transformer or a reactor.

[Background of the invention]

An iron core for a stationary inductor, for example, a single-phase two-leg iron core used in an iron-type transformer, is joined together at the overlapping part of the leg iron and yoke, and the steel plates that make up the leg iron and yoke are joined together. It is constructed by stacking a large number of blocks with different widths to form a roughly circular shape. Such a configuration is shown in FIGS. 1 and 2.

Figure 1 is a plan view showing a conventional single-phase two-leg core laminated steel plate;
Figure 2 is a sectional view of the leg iron. In the figure, ##1 is a leg iron and 2 is a yoke. The leg iron 1 and the yoke 2 are abutted and joined at both ends thereof. A plurality of joining steel plates of the leg iron 1 and the yoke 2 are laminated like this, but the leg iron 1
In order to ensure that the iron core consisting of the leg irons 1 and yoke 2 is tightened and integrated, the joints between the leg irons 1 and the yoke 2 are staggered for each steel plate as shown in FIG. Reference numeral 3 indicates an overlapping portion that is a portion between these shifted joint portions. As is clear from FIG. 2, in the laminated steel plate shown in FIG. 1, steel plates with equal widths are stacked to form one block, and blocks with different widths are sequentially stacked to form an iron core. The width of the block increases sequentially from both outer sides toward the inner side. Therefore, the single leg iron and the yoke have a substantially circular cross section, and the winding can be attached without any problem.

By the way, in the configuration of an iron core having such a joint part, an overlap part 3 occurs at the joint part, and this overlap part 3
It is known that iron loss and magnetostrictive vibration increase, which in turn increases excitation current and noise. Although the cause has not been clearly elucidated, it is presumed that due to the presence of the joint, magnetic flux passes through the steel plate adjacent to the joint, resulting in an increase in the magnetic flux density in that part. Here, the relationship between the width of the overlapping portion 30 and iron loss is investigated as follows.

Figure 3(a) is a plan view of the overlapping part of the laminated steel plates;
b) is a graph showing the relationship between the width of the overlapping portion and iron loss.

In FIG. 3(a), steel plates having a width l are used for the leg iron 1 and the yoke 2, and the overlapping portion 3 at the joint thereof has an overlap having a width Δl. The width of this steel plate! The ratio Δ of the width Δl of the overlapped part
The relationship between 2/1 and iron loss is shown in the graph of FIG. 3(b). That is, the iron loss increases almost linearly as the ratio ΔJ// increases.

Conventionally, in a stationary inductor core, the overlap portion 30 width Δ
l was always held constant. Therefore, in a configuration where the width of the block gradually increases toward the inside as shown in Figure 2, there will be a drawback that the core loss will increase in the core surface layer where the ratio Δ1/1 increases. .

FIG. 4 is a plan view of the overlapping portion of conventional laminated steel plates that improves the above-mentioned drawbacks. In this configuration, leg iron 1 and yoke 2
By shifting the overlapped part 30 width Δ, the width Δ!
0, Δノ2, Δ! It is changed to 3. Such a configuration is shown as a conventional example in Japanese Patent Publication No. 49-9809. However, in such a configuration, the same steel plate width l
Since we only change the width Δ of the overlapping part within the same core block having This does not essentially improve the conventional core configuration shown in FIGS. 3 to 3, and large core losses still occur.

[Purpose of the invention]

An object of the present invention is to provide an iron core for a stationary inductor that can eliminate the above-mentioned conventional drawbacks, reduce iron loss and magnetostrictive vibration, and further reduce excitation current and noise.

[Summary of the invention]

In order to achieve this object, the present invention provides an iron core constructed by laminating steel plates of the same width to form a block, and combining a plurality of blocks of different widths. Width Δ of the overlap part! And the width of the steel plate! Which ratio Δ
! /! is characterized in that it is configured so that it is approximately constant for all blocks that make up the iron core.

[Embodiments of the invention]

The present invention will be explained below based on the illustrated embodiments.

FIGS. 5(a) and 5(b) are plan views of the overlapping portion of the laminated steel plates of the single-phase, two-leg iron core according to the first embodiment of the present invention, and FIG.
) is a graph showing the relationship between the core thickness and iron loss shown in FIGS. 5(a) and 5(b). FIG. 5(a) shows the steel plate of the central block of the iron core, and its leg iron 1 and yoke 2.
The width l is the maximum width of the iron core. In this case, the overlap part 3
The overlap width is Δ and the ratio is Δt/l. - Figure 5(b) shows a steel plate of a block near the surface layer of the core, and the width of the leg iron 1 and yoke 2 is half the width l of the steel plate shown in Figure 5(a). , that is, the width is 0.5 mm. In this embodiment, the width of the overlapped portion 30 in this case is set to be the width Δ! without, width 0.5Δ
It is intended to be Therefore, the ratio of the width of the steel plate to the width of the overlapping part is 0.5Δ110.51=Δ1/1,
It is equal to the ratio in the block in the center of the core. In this way, the width of the overlapping portion 30 is set for all blocks so that the ratio of the width of the block to the width of the steel plate is the same.

Iron loss, overlap width Δl, and steel plate width! The ratio Δl/! has the relationship shown in FIG. 3(b). However, as in the conventional configuration, the width of the overlap Δ! is the same for all blocks, the iron loss in a core with a cross section as shown in Figure 2 is lowest at the center of the core, as shown by the dotted line E in Figure 5(C), and at the surface of the core. It increases as you get closer. On the other hand, if the ratio Δ1/1 of each block is made constant as in this embodiment, the result is shown in FIG. 5(C).
As shown by the solid line F, each block is equal. In this case, the iron loss is the ratio Δ! based on the maximum width of the steel plates in the core. /! Determining is the minimum. However, if it is not possible to use the maximum width steel plate as a standard due to mechanical strength or iron loss margin when configuring the iron core, selecting a steel plate width other than the maximum width as a standard can reduce the iron loss arbitrarily. can be held constant at the value of .

In this way, in this example, the ratio Δ11/1 between the width Δ of the overlapping part and the width of the steel plate is constant for each block.
It is possible to achieve constant low iron loss and low magnetostrictive vibration in the iron core, and it is possible to reduce excitation current and noise.

FIG. 6 is a graph showing the relationship between the thickness of the core and the core loss when a two-legged core according to the second embodiment of the present invention is used. In this embodiment, as shown in the figure, the core surface layer A
The ratio Δl/l of the width Δl of the overlapping part and the width l of the steel plate in (one or more blocks) is calculated as the ratio Δtt/l in the central part B.
It is configured so that it increases somewhat from it. The degree of increase is determined by various conditions, but is estimated to be about several tens of percent. In this case, the iron loss increases in the core surface layer A as shown by the solid line G, but the degree of increase is extremely small (the dotted line E
It is clear that the iron loss is sufficiently improved compared to the iron loss of the conventional configuration shown in FIG.

In this way, in this embodiment, the width Δ! of the overlapped portion! Since the ratio Δt/i of the steel plate width and the width 1 of the steel plate is slightly increased only in the surface layer of the iron core, it is possible to achieve almost the same effect as in the example of the rabbit. In addition, when configuring the core, it is difficult to obtain a certain level of assembly accuracy as the surface layer of the core gets closer, and the strength of the core joint decreases. Since it can be made larger than in the case of the embodiment, a margin for assembly precision and core joint strength can be ensured.

7 to 9 are the third, fourth, and fifth embodiments of the present invention, respectively.
It is a top view of the laminated steel plate of the 3rd leg iron core based on the Example of 3. Figure 7 shows the lamination of steel plates using an economical joining method in which the leg iron 1 and the yoke 2 are cut to avoid scrap, and the overlap between the leg iron 1 and the yoke 2 at the center leg. In other overlapped parts 3 excluding part 4, overlapped part 30
Width Δ] and steel plate width! The ratio Δ! /! is constructed so that it is almost constant.

Figures 8 and 9 show the lamination of steel plates including the overlapping part of the leg iron 1 and the yoke 2 at the center leg, and in the steel plate shown in Figure 8, a V-shaped cut is formed in the yoke 2. In the case of the steel plate shown in FIG. 9, the leg iron 1 is joined to the leg iron 1 through the cut portion of the yoke 2. In either case, the central leg has an overlapping portion 5. In such a configuration, the ratio Δ1/1 of the width Δl of the overlapped portions 3 and 50 and the width j of the steel plate is substantially constant.

In this way, in the third, fourth, and fifth embodiments,
Since the ratio Δt/l of the width Δl of all the overlapping parts of the three-layer, three-leg iron core to the steel plate width l is substantially constant, the same effects as in the first and second embodiments are achieved.

FIG. 10 is a plan view of an overlapping portion of laminated steel plates of a stationary inductor core according to a sixth embodiment of the present invention.

In this embodiment, the width l of the leg iron 1 and the width ]' of the yoke 2 are different,
width! ' is made several percent larger than the width l, and the structure is designed to further improve iron loss characteristics. In such a configuration, the ratio between the width Δj' of the overlapped portion 60 and the width of the steel plate is the maximum yoke width l! The iron core is set based on the ratio Δl//J
/ is configured to be approximately constant in all blocks.

・Thus, in this example, the larger of the leg iron width and the yoke width was selected as the steel plate width, and with this as a reference, the ratio to the overlap width was kept almost constant. , the same effects as the first and second embodiments are achieved.

〔Effect of the invention〕

As described above, in the present invention, the iron core is configured so that the ratio of the width of the overlapping part at the joint between the leg iron and the yoke to the width of the steel plate is approximately constant for each block, so that iron loss and magnetostriction are reduced. It is possible to reduce vibration, excitation current and noise.

[Brief explanation of the drawing]

Figure 1 is a plan view showing a conventional single-phase two-leg core laminated steel plate;
Figure 2 is a cross-sectional view of the leg iron shown in Figure 1, Figure 3 (a) is a plan view of the overlapping part of the laminated steel plates, and Figure 3 (b) is the relationship between the width of the shaped part and iron loss. The graph shown in Fig. 4 is a plan view of the overlapping part of laminated steel plates of another conventional example, and Fig. 5<->, (b)
5(C) is a plan view of the overlapping portion of the laminated steel plates of the single-phase two-leg iron core according to the first embodiment of the present invention, and FIG. 5(C) is a plan view of FIG.
Graph showing the relationship between core thickness and iron loss shown in b), No. 6
The figure is a graph showing the relationship between core thickness and iron loss when a single-phase two-leg iron core according to the second embodiment of the present invention is used, and FIGS. 10 is a plan view of the overlapping portion of the laminated steel plates of the core for a stationary inductor according to the sixth embodiment of the present invention. FIG. . 1... Leg iron, 2... Yoke, 3,5.6
・・・・・・Overlapping part. Figure 1 Figure 2 Figure 3 (a) (b) Δl/l-+ Figure 4? Figure 5(a) (
b) (C) Iron loss □ Figure 6 Figure 7 Figure 8

Claims (1)

[Scope of Claims] 1. In an iron core constructed by combining a plurality of blocks of different widths, with each laminated steel plate of the same width being one block, the overlap at the joint between the leg iron and the yoke of this iron core. An iron core for a stationary inductor, characterized in that the ratio between the width of the section and the width of the steel plate is substantially constant for all of the blocks. 2. In claim 1, the iron core is. An iron core for a stationary inductor characterized by a structure in which the width of the steel plate in each block increases from the surface layer to the center. 3. Claim 2 is characterized in that the surface layer block in each of the blocks is configured such that the ratio of the front overlapping corridor to the width of the steel plate is larger than the ratio of the central block. Iron core for stationary inductor.